Toxic Plant Questions

  • Published: Friday, May 22, 2020

buttercup plants

Pasture being overtaken by buttercup

This spring has brought an unusual number of questions from cattlemen about poisonous plants. Fortunately, most did not involve a death situation but rather a curiosity of what is that plant in my pasture?

One of the more asked questions was about the pretty yellow, flowered plant in my horse pasture. In all likelihood the answer to that question is buttercup. It has a shiny, bright yellow bloom and does seem to show up in horse pastures and other heavily grazed fields in early May.  It is a perennial and all parts of the plant, if grazed, are poisonous. However, when dried in hay, the toxin is inactivated and safe for animals to eat.  A variety of herbicides can control it if applied in late fall or early spring.

Cow stripping fescue seedheads

Cow stripping fescue seedheads

Other toxic plants I’ve had questions about this spring are wild cherry, hairy vetch, poison hemlock, perilla mint and of course, johnsongrass. Actually, I could probably add fescue to the list. The ergot alkaloids produced by some fescue varieties cause much more economic losses than the poisonous plants listed previously.

The good news is even though livestock have numerous poisonous plants around them, they seldom eat them. If they do eat them they don’t consume enough to cause serious problems. The exception is when the animals are forced to eat them or their mothers never told them as a youngsters to avoid certain plants.

Close-up of ergot

Close-up of ergot

Fescue is an exception as in late May and very early June cattle seem to crave fescue seedheads. That’s when ergot compounds are elevated in the stem and seedheads. Those alkaloids cause heat-stress problems in the animals for an extended period of time. This results in reduced daily gains, elevated body temperatures and poor reproductive performance.

Writer: Eldon Cole

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Eldon Cole

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